Such touch fastener elements also include mechanical fastening elements with touch fastener elements made in a complementary manner to form a fastener which can be repeatedly opened and closed. Hooks or mushroom-like fastener elements interact with loop-like fastener elements of another touch fastener element forming of a touch fastener. Solutions are also known in which the same touch fastener elements of two different touch fastener elements interact with one another (hermaphroditic fastener).
DE 699 22 264 T2 discloses supplying a belt-like support part with a plurality of projecting stem parts to a molding gap between heatable molding rolls. Into that gap by an extrusion means, an additional molding belt of plastic material can be supplied as the actual molding tool with mold recesses shapes. The hot stem ends of the stem parts are molded into head parts to obtain a mushroom-like touch fastener element. Since the head parts are formed from the plastic material of the stem parts, the head parts are of smaller dimension due to low material charging in the free and therefore projecting head surface available for interlocking. This limitation can adversely affect the required adhesion forces.
Conversely, U.S. Pat. No. 6,180,205 B1 proposes a production method using a molding roll in which a belt-like support part can be connected to a plurality on touch fastener elements dimensionable to be relatively large. For this purpose, the molding roll on its outer periphery has hook-shaped mold recesses into which plastic material is pressed to fill the mold by a first extruder means. Excess plastic material on the outer peripheral side of the molding roll is removed by a cutting removal device technically referred to as a doctor blade. By a second extruder located downstream in the production direction, the support part material is then applied and permanently connected to the hook-shaped fastener elements during the cooling process of the roll. A stripper roll then removes the finished fastener element from the mold. Due to the hook geometry, difficulties can arise during the mold removal process. Furthermore, a relatively high proportion of plastic scrap is formed in the production process due to use of the doctor blade.
WO 2006/099000 A2 discloses spraying a belt-like conveyor device on its upper strand side with droplets of plastic material. The plastic material is molded based on its surface tension into hemispherical shell bodies. Then bodies are permanently connected on their arching tops to a belt-like support part with the formation of a touch fastener element. In a development of this solution it is also possible, in the manner of thickened stem parts, to supply a belt-like support part which on its top bears grain-shaped agglomerates as the stem parts onto which the hemispherical head parts can then be placed. The touch fastener element produced in this way and designed to be used in particular as a fastener for baby diapers or incontinence diapers is, however, made relatively stiff and leaves much to be desired with respect to the fastener characteristics.
US 2006/0220271 A1 discloses a comparable solution calling for a molding tool in the form of a molding roll with the corresponding mold recesses instead of a belt for production of hemispherical fastener elements. Production of stem parts between the head parts and support part is not done with this known solution.
U.S. Pat. No. 5,785,784 discloses a production method for producing a belt-like support part bearing a plurality of projecting stem parts. In a downstream production step, the free stem ends are heated and then thicken as a result of the surface tension of the plastic material, in particular into a hemispherical head part. If, in a continuation of the known solution, the head parts produced in this way can be reshaped by a calander rolling method. Widened head part geometries are then formed which, with respect to the low material charge, are made relatively small and are widened in the direction of the earlier rolling direction.
DE 693 11 107 T2 discloses a generic method for producing a plastic touch fastener element with a base as a support part and with several stem parts, each having a proximal end projecting from the support part and a distal end provided with a head part, with the following method steps:    a) providing a permanent support part mold as a first molding tool for molding the support part of the touch fastener element;    b) providing a non-permanent stem part mold as a second molding tool with several passages for molding the stem parts; and    c) providing a permanent head part mold as the third molding tool with several cavities for molding the head parts; and    d) attaching the non-permanent stem part mold to the support part mold such that the passages of the stem part mold are in a fluid connection to the cavity of the support part mold and attaching the head part mold to the non-permanent stem part mold such that the cavities of the head part mold are in a fluid connection to the passages of the nonpermanent stem part mold.
By injecting a suitable molten plastic into the three molding tools in conjunction with curing of the plastic, a plastic touch fastener element is formed. By separation of the head part mold from the support part mold together with removing the non-permanent stem part mold, the touch fastener element removed from the mold in this way is present as a commercial product. The known solution moreover relates to a molding device characterized by three different molding tools and formed from the permanent support part mold, the permanent head part mold and the nonpermanent stem part mold. Due to the plurality of individual molds that must be made available and that must be handled in the production process, a certain preparation and production effort is necessary.